Five Electrons Are in a Two-Dimensional Square Potential Energy Well

Multiple Choice

Five electrons are in a two-dimensional square potential energy well with sides of length L. The potential energy is infinite at the sides and zero inside. The single-particle energies are given by where n_x and n_y are integers. In units of (h²/8mL²) the energy of the ground state of the system is

A) 0
B) 10
C) 19
D) 24
E) 48